Ordered Mesoporous Carbon Decorated with Magnetite for the Detection of Heavy Metals by Square Wave Anodic Stripping Voltammetry

Abstract

In this work, oxidized ordered mesoporous carbon (OMC-OXI) decorated with magnetite (OMC-OXI-Fe) was synthesized via a soft template technique in combination with a solvothermal method. The OMC-OXI-Fe was characterized by Raman spectroscopy, X-ray diffraction, nitrogen adsorption-desorption, scanning electron microscopy and thermal gravimetric analysis, indicating that the material keeps the OMC structure. The prepared material was used as an electrochemical sensor for the single and combined detection of Cd(II), Cu(II), Hg(II), and Pb(II) ions by square-wave anodic stripping voltammetry (SWASV). The electrochemical results showed that incorporation of magnetite did not modify the charge transfer properties, and maintained the available surface area for the metal ion detection. OMC-OXI-Fe presented a very favorable sensitivity (145.75 μA mg−1 L) and LOD (1.57 μg L−1) for Pb(II), while the responses to Cu(II), Cd(II) and Hg(II) were much lower. These results indicated that the magnetic properties of the modified electrode increased the individual sensitivity for Pb(II) detection and maintained the capacity of simultaneous detection for the studied heavy metal ions. The combination of magnetic mesoporous carbon and electrochemical pulse techniques is a suitable and practical alternative method for the electrochemical detection of hazardous metallic ions in water for human use.